Tuned potential pedestal for mask etch processing apparatus

ABSTRACT

The present invention generally provides an improved pedestal for supporting a substrate. The pedestal has greatest application during a plasma etching process, such as for a quartz photomask, or “reticle.” The pedestal defines a body, and a substrate support base along an upper surface of the body. The substrate support base has an outer edge, and an intermediate substrate support ridge for receiving and supporting the substrate. At least a portion of the substrate support base outside of the intermediate substrate support ridge is fabricated from a dielectric material. The purpose is to couple greater RF power through the reticle in order to enhance the plasma etching process.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority to previously filed provisionalpatent application Ser. No. 60/531,062, filed Dec. 19, 2003, entitled“Tuned Potential Pedestal for Mask Etch Processing Apparatus.” Theprovisional application is incorporated herein by referenced in itsentirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention generally relates to the fabrication of integratedcircuits. More specifically, the invention relates to an apparatus formanufacturing a photomask, or “reticle,” useful in manufacturingsemiconductors.

2. Description of the Related Art

Integrated circuits (IC) are manufactured by forming discretesemiconductor devices on a surface of a semiconductor substrate. Anexample of such a substrate is a silicon (Si) or silicon dioxide (SiO₂)wafer. To interconnect the devices on the substrate, a multi-levelnetwork of interconnect structures is formed. Material is deposited onthe substrate in layers and selectively removed in a series ofcontrolled steps.

Increasing circuit densities have placed additional demands on processesused to fabricate semiconductor devices. For example, as circuitdensities increase, the widths of vias, contacts and other features, aswell as the dielectric materials between them, decrease to sub-microndimensions. However, the thickness of the dielectric layers remainssubstantially constant, with the result that the aspect ratios for thefeatures, i.e., their height divided by width, increases. Reliableformation of high aspect ratio features is important to the success ofsub-micron technology and to the continued effort to increase circuitdensity and the quality of individual substrates and die.

Reliable formation of high aspect ratio features with desired criticaldimensions requires precise patterning and subsequent etching of thesubstrate. A technique commonly used to form precise patterns onsubstrates is photolithography. The technique generally involves thedirection of light energy through a lens, or “reticle” and onto thesubstrate. In conventional photolithographic processes, a photoresistmaterial is first applied on a substrate layer to be etched. In thecontext of optical resists, the resist material is sensitive to lightenergy, such as ultraviolet or laser sources. The resist materialdefines a polymer that is tuned to respond to the specific wavelength oflight used, and to different exposing sources.

After the resist is deposited onto the substrate, the light source isactuated to emit ultraviolet (UV) light or low X-ray light, for example,directed at the resist-covered substrate. The selected light sourcechemically alters the composition of the photoresist material. However,the photoresist layer is only selectively exposed. In this respect, aphotomask, or “reticle,” is positioned between the light source and thesubstrate being processed. The photomask is patterned to contain thedesired configuration of features for the substrate. The patternedphotomask causes the light energy to strike the resist material inaccordance with the pattern.

Photolithographic reticles are fabricated from an optically transparentmaterial, such as quartz (i.e., silicon dioxide, SiO₂). The reticleincludes a pattern of opaque material that inhibits the light fromexposing portions of the substrate in accordance with the desiredpattern. A thin opaque layer of metal, typically chromium, is disposedon the surface of the reticle. This light-shielding layer is patternedto correspond to the features to be transferred to the substrate, suchas transistors or polygates. The metallic material is patterned usingconventional laser or electron beam patterning equipment to define thecritical dimensions to be transferred to the metal layer. The metallayer is then etched to remove the metal material not protected by thepatterned resist, thereby exposing the underlying quartz material andforming a patterned photomask layer. Photomask layers thus allow lightto pass therethrough in a precise pattern onto the substrate surface.

In photolithography, the exposed material may either be a positiveresist or a negative resist. In a positive resist, the exposed resistmaterial on the substrate is removed, while in a negative resist, theunexposed portions are removed. Removal is typically by a chemicalprocess to expose an underlying substrate material. The exposedunderlying substrate material may then be etched to form patternedfeatures in the substrate surface while the retained resist materialremains as a protective coating for the unexposed underlying substratematerial. In this manner, contacts, vias, or interconnects may be formedby exposing the resist to a pattern of light through a photolithographicreticle having a photomask layer disposed thereon.

In an iterative convergence, the method for fabricating a patternedreticle itself involves a deposition and subsequent etching process. Inthis respect, a metal layer is first deposited on a top surface of aglass reticle. Thereafter, selected portions of the metal layer areremoved through etching. Various types of etching processes are used foretching the metal layer from a reticle. One such etching method is knownas plasma etching. In order to perform plasma etching, a glass reticleis first placed within a process chamber. More specifically, the glassreticle is placed on a pedestal. In a plasma etching process, thepedestal serves as a cathode. To this end, the metallic pedestal isgiven RF power. Power applied to the pedestal creates a substrate biasin the form of a negative voltage on the upper surface of the reticle.This negative voltage is used to attract ions from a plasma formed abovethe reticle in the chamber. The plasma is formed by the application ofpower to one or more inductive coils at the top of the chamber. Theinductive coils generate and sustain the plasma above the pedestal andreticle. Thus, a voltage drop is induced across the pedestal that drawsions to the upper surface of the reticle, thereby etching a metalliclayer.

Because the reticle is formed from a material having a low dielectricconstant, e.g., glass or quartz, the amount of RF power that is coupledthrough the reticle is low. This inhibits the gas plasma in reactingwith the reticle surface. This limitation is compounded by a gaptypically existing between the reticle and the supporting pedestaltherebelow. In addition, when the surface area of the pedestal is largecompared to the reticle area, the RF power may preferentially couple toother regions of the pedestal, producing a loss of RF power. Further, ithas been observed that the use of a pedestal cover, e.g., cover ring andcapture ring, fabricated from a dielectric material is inadequate tolessen the power coupled through the region of the pedestal that is notimmediately below the reticle.

Therefore, there is a need for a plasma etching apparatus that aids inthe chemical reaction between a gas plasma and a reticle. In addition,there is a need for a pedestal fabricated from a material that does notcontribute to the power loss across the reticle during a plasma etchingprocedure.

SUMMARY OF THE INVENTION

The present invention generally provides an improved pedestal forsupporting a substrate and related substrate support hardware. Thepedestal has greatest application during a plasma etching process, suchas for a quartz photomask, or “reticle.”

The pedestal defines a body, and a base along on an upper surface of thebody. The body receives an RF power during substrate processing. Thesubstrate support base has an outer edge, and an intermediate substratesupport ridge for receiving and supporting the substrate. At least aportion of the substrate support base outside of the intermediatesubstrate support ridge is fabricated from a dielectric material, ormaterial having a lower dielectric constant than the remaining supportbase. An example is quartz. Quartz has a lower dielectric constant thanthe materials typically used for fabricating the pedestal body or cover,e.g., alumina. The placement of quartz allows greater RF power to becoupled through the reticle, thereby enhancing the plasma etchingprocess. It also provides greater control over the relative amount of RFpower coupled through the reticle.

In one aspect, a layer of dielectric material is placed along the top ofthe support base of the pedestal body. In another embodiment, the entirecross-sectional thickness of the support base that encompasses thesupporting ridge is fabricated from a dielectric material. In oneembodiment, a separate substrate support assembly is disposed on thebase to facilitate the transfer of the substrate onto and off of thepedestal, with the substrate support assembly being fabricated from adielectric material.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the above recited features of the presentinvention can be understood in detail, a more particular description ofthe invention, briefly summarized above, may be had by reference to theappended drawings. It is to be noted, however, that the appendeddrawings illustrate only typical embodiments of this invention and are,therefore, not to be considered limiting of its scope.

FIG. 1 is a cross-sectional view of a plasma etching chamber as mightcontain the pedestal of the present invention. The chamber shown in FIG.1 is exemplary.

FIG. 2 presents an exploded perspective view of the substrate supportmember of FIG. 1.

FIG. 3 shows a perspective cutaway view of one embodiment of a pedestalof the present invention.

FIG. 4 provides a cross-sectional schematic view of a pedestal of thepresent invention. A portion fabricated from a dielectric material isshown.

FIG. 5 presents a cross-sectional schematic view of a pedestal of thepresent invention, in an alternate embodiment. A portion fabricated froma dielectric material is again shown.

DETAILED DESCRIPTION OF THE INVENTION

Aspects of the invention will be described below in reference to aninductively coupled plasma etch chamber. Suitable inductively coupledplasma etch chambers include the Decoupled Plasma Source (DPS™) chamberavailable from Applied Materials, Inc., of Santa Clara, Calif., or theETEC Tetra™ photomask etch chamber available from ETEC of Hayward,Calif. A two-coil chamber, such as the Tetra II™ decoupled plasma sourcechamber available from Applied Materials, Inc. may also be employed.Other process chambers may be used including, for example, capacitivelycoupled parallel plate chambers and magnetically enhanced ion etchchambers, as well as inductively coupled plasma etch chambers ofdifferent designs. Although the processes are advantageously performedwith the DPS™ processing chamber, the description in conjunction withthe DPS™ processing chamber is illustrative and should not be construedor interpreted to limit the scope of aspects of the invention.

In order to perform plasma etching, a substrate, e.g., a glass reticle,is placed within a processing chamber. An example of such a chamber isschematically shown in FIG. 1. The process chamber 100 of FIG. 1 has asubstrate support member 200 disposed therein, and a substrate handlerblade 300 positioned adjacent thereto. Substrates 222 are shownpositioned on both the substrate support member 200 and the handlerblade 300.

The processing chamber 100 is configured to receive a substrate 222,such as a glass reticle to be processed through plasma etching. Thesubstrate 222 enters and exits the chamber 100 through a gate 161. Thegate 161 serves as a port, and also isolates the chamber 100 environmentduring reticle processing. The substrate 222 is transported via asubstrate cassette, using the substrate handling blade 300. Thesubstrate handling blade 300 transfers the substrate 222 between aseparate transfer chamber (not shown) and various processing chambers.In this respect, it is understood that the reticle fabrication processinvolves multiple steps, and that different steps are typicallyconducted in different chambers that mechanically cooperate with thesubstrate handling blade 300. An example of such a processing system isa Centura™ processing system available from Applied Materials, Inc. ofSanta Clara, Calif.

The process chamber 100 generally includes a cylindrical side wall 162.The side wall 162 helps define the chamber body, and also supports thegate 161. The chamber 100 is also defined by a chamber bottom 167, andan energy transparent ceiling or lid 163. An inductive coil 176 isdisposed around at least a portion of the lid 163. The chamber body 162and chamber bottom 167 of the chamber 100 can be made from a metal, suchas anodized aluminum. The lid 163 is fabricated from an energytransparent material such as a ceramic or other dielectric material.

As mentioned above, the chamber 100 holds a substrate support member200. The support member 200 supports the substrate 222 duringprocessing. A plasma zone 164 is defined by the process chamber 100above an upper surface of the substrate support member 200. Duringprocessing, process gases are introduced into the plasma etch chamber100 through a gas distributor 172. The gas distributor 172 isperipherally disposed about the substrate support member 200. The gasdistributor 172 is shown illustratively, and may be disposed in otherconfigurations, such as disposed at the top of lid 163. Process gasesand etchant byproducts may be exhausted from the process chamber 100through an exhaust system (not shown). An optional cooling line 184 isprovided in the pedestal 200. for controlling the pressure in the plasmaetch chamber 100. An endpoint measurement device may optionally beincluded to determine the endpoint of a process performed in the chamber100.

With respect to the substrate support member 200 itself, the supportmember 200 defines a pedestal for the substrate 222 during processing.The support member 200 first comprises a body 206. The body 206 has anupper surface that defines a substrate support base 210 (seen in FIG.2). In one arrangement, the substrate support base 210 is a separatepiece mounted on an upper surface of the body 206. An optional substratesupporting assembly 215 is preferably provided over the base 210 to aidin transporting the substrate 222 into and out of the chamber 100. Thesubstrate supporting assembly 215 is shown in detail in FIG. 2. Only thecapture ring 216 of the supporting assembly 215 is seen in FIG. 1.

Referring back to FIG. 1, the body 206 of the substrate support member200 is mounted on a bulk head assembly, or shaft, 102. In the embodimentshown, the body 206 is stationary in the chamber 100; however, in analternative embodiment, the body 206 (or a portion of the body 206) maybe moveable within the chamber 100. In one arrangement, the body 206 ofthe substrate support member 200 is mounted on a stainless steel base104. The base 104 is typically disposed on the bottom of the processingchamber (not shown in FIG. 2), with the bulk head assembly 102 mountedthrough the bottom of the processing chamber 100 and coupled to the body206. The substrate support member 200 is adapted to maintain vacuumisolation between the interior of the chamber 100 and the outsideenvironment. Power, electrical controls, and backpressure gases may beprovided to the substrate support member 200 via the shaft 102.

FIG. 2 presents an exploded perspective view of one embodiment of asubstrate support member 200. From FIG. 2, the body 206 and support base210 are more clearly seen. It can also be seen that a cathode 112 isdisposed in the support base 210. The cathode 112 may optionallyvertically extend above the surface of the body 206. The cathode 112 iselectrically coupled to an electrode power supply 178 to generate acapacitive electric field in the plasma etch chamber 100. Typically anRF voltage is applied to the cathode 112 while the chamber body 162 iselectrically grounded. Power applied to the pedestal 200 creates asubstrate bias in the form of a negative voltage on the upper surface ofthe substrate 222. This negative voltage is used to attract ions fromthe plasma formed in the chamber 100 to the upper surface of thesubstrate 222. The capacitive electric field forms a bias whichaccelerates inductively formed plasma species toward the substrate 222to provide a more vertically oriented anisotropic etching of thesubstrate 222.

Channels 211 (three are shown) are also disposed through the body 206,and house internally movable lift pins 214 therein. As will be discussedfurther below, the lift pins 214 engage the lower surface of a capturering 220 to move the capture ring 220 vertically within the chamber 100relative to the cover ring 216. The body 206 may comprise a temperaturecontrolled base adapted to regulate the temperature of the substratesupport assembly 215, and thus, a substrate 222 disposed thereon. Thebody 206 can be made of a material inert to the process formed in theprocessing chamber including, for example, aluminum oxide, or aluminum,and substrate support assembly 215 components can be made of aluminum oraluminum oxide. The body 206 may include fluid channels, heatingelements, e.g., resistive heating elements or other temperature controlmembers.

In the support member arrangement of FIG. 2, the substrate supportmember 200 includes a separate substrate supporting assembly 215. Thesubstrate supporting assembly 215 generally includes a cover ring 216and a capture ring 220.

Referring first to the cover ring 216, the cover ring 216 is preferablya circular ring having an upper surface 219 and support shoulders 218.The substrate supports 218 define shoulders for receiving a substrate(not shown). In one arrangement, the substrate supports 218 defineopposing raised surfaces 221, 223 that each includes an inner slopedsurface for receiving a substrate. A central opening 225 is formed inthe upper surface 219 of the cover ring 216. The two raised surfaces221, 223 are generally disposed on opposing sides of the central opening225. The first raised surface 221 defines an essentially linear raisedsurface extending along the length of one side of the central opening225. The second raised surface 223 defines an arcuate raised surface 221having an outer diameter 224 and an inner diameter 226. The outerdiameter 224 generally matches the radius of the cover ring 216, whilethe inner diameter 226 conforms to the geometry of the central bore 225along one or more sides of the bore 225. The upper surface 219 and theraised surfaces 221, 223 may be monolithic or may be made of separatecomponents connected together.

The capture ring 220 defines an arcuate base plate having an innerdiameter 207 and an outer diameter 202. A central bore 206 is formedwithin the inner diameter 207 of the capture ring 220. The diameters207, 202 of the capture ring 220 are not continuous, but retain anopening that serves as part of the bore 206. As with the cover ring 216,the capture ring 220 includes substrate supports 204, 205. The substratesupports 204, 205 generally follow the inner diameter 207 of the capturering 220. In the arrangement of FIG. 2, the supports 204, 205 defineshoulders disposed along the inner perimeter 207. The substrate supports204, 205 and the base plate 202 form a substrate receiving area. Theshoulders 204, 205 and the base plate 202 are adapted to mate with thesubstrate supports 218 on the cover ring 216. When the capture ring 220is rested upon the cover ring 216, the substrate supports 205 for thecapture ring 220 are co-planar with the substrate supports 218 for thecover ring. The capture ring 220 is dimensioned to rest on the coverring 216 without covering the two raised surfaces 221, 222 on the coverring 216. Together, the substrate supports 205, 218 may then seamlesslyreceive a substrate (not shown).

The capture ring 220 moves vertically above the cover ring 216. Inoperation, the lift pins 214 move the capture ring 220 vertically abovethe cover ring 216 during substrate transfer, and then lower the capturering 220 onto the cover ring 216 for substrate processing. The use oflift pins in the semiconductor fabrication business is known, and thoseof ordinary skill in the art will understand from this disclosure howthe lift pins may be fabricated.

Channels 217 are formed through the cover ring 216 to enable the liftpins 214 disposed through the body 206 to move therethrough and lift thecapture ring 220 vertically. The vertical movement imparted by the liftpins 214 is used to lift the capture ring 220 to effectuate substratetransfer between the substrate handler blade 300 and the capture ring220. The lift pins 214 move the capture ring 220 vertically above thecover ring 216 during substrate transfer, and then lower the capturering 220 onto the cover ring 216 for substrate processing.

To begin processing, the reticle 222 (or other substrate) is positionedon the surface of the pedestal 200. Etch gases are then introduced intothe chamber 100. To this end, a process gas source supplies gas, such asan oxygen based gas, through a gas input line 172. In the arrangement ofFIG. 1, the input line 172 feeds gas into the side of the lid 163.However, gas may also be introduced through nozzles (not shown) in thetop of the lid 163. Chamber pressure is controlled by a closed-looppressure control system (not shown).

As gas is injected into the chamber 100, a gas plasma is created. Plasmais formed by the application of power to one or more inductive coils 176at the top of the lid 163. In the chamber 100 of FIG. 1, two RF coils176 are used, with one being an outer coil and one being an inner coil.A power supply 177 and matching network is used to apply power to theinductive coils 176. The inductive coils 176 generate and sustain theplasma above the pedestal 200 and substrate 222. In one arrangement,approximately 125 Watts is applied to the coils 176 at a frequency ofabout 13.56 MHz, to produce and maintain an oxygen-comprising plasmaover the surface of the reticle 222. In one arrangement for a dual coilsystem, approximately 400 Watts is applied to the coils 176 at afrequency of about 13.56 MHz, to produce and maintain achlo7rine-and-oxygen-comprising plasma over the surface of the reticle222. For a single coil system, the coils may provide a DC bias of about340 to 410 Volts on the reticle surface.

FIG. 3 shows a perspective cutaway view of one embodiment of a pedestal300 of the present invention. The pedestal 300 is configured to receiveand support a substrate in a plasma etching chamber. Preferably, thesubstrate is a photolithographic reticle, and the chamber is a plasmaetching chamber, such as the chamber shown in FIG. 1, and discussedabove.

The pedestal first comprises a body 306. In the arrangement of FIG. 3,the body 306 is a generally cylindrical object, though other shapes maybe employed. The body 306 includes an upper surface 310 that serves as asubstrate support base. In the arrangement shown in FIG. 3, the supportbase 310 has a radial outer diameter 324. The base 310 also has anintermediate shoulder 326 that forms a four-sided support ridge 325. Thesupport ridge 325 serves to support the reticle above the pedestal 300during processing. The support ridge 325 is preferably fabricated from ametallic material. The term “support ridge” means any raised surfacefeature of any height or shape along the support base 310 that contactsand supports a substrate 222 during processing.

The support base 310 is typically configured to receive a cover (notshown) to further support a reticle during processing. The cover may beconfigured to operate as the substrate support assembly 215 describedabove.

In the novel pedestal 300 of the present invention, at least a portionof the body 306 is fabricated from a dielectric material. In the cutawayview of FIG. 3, the dielectric material portion of the body 306 is shownat 318. Dielectric material 318 is selectively used in the upper surface310 so as to define a dielectric ring generally about the perimeter ofthe body 306. The dielectric material 318 is placed outside of thecontact point, e.g., support ridge 326, for the reticle 222 on thepedestal 300. The dielectric material portion 318 of the body 306 maycomprise two or more separate components (not shown) joined together toform the dielectric portion 318 of the body 306. The two or moredielectric members may be fabricated from materials having differentdielectric properties. The benefit of using material of differentdielectric properties is to control the relative amount of RF powercoupled through the reticle, as the thickness and dielectric property ofthe reticle substrate, e.g., quartz, is fixed.

The dielectric material portion 318 of the body 306 may be of differentthicknesses. This is demonstrated in the schematic embodiments shown inFIGS. 4 and 5. FIG. 4 provides a cross-sectional view of a pedestal 300′of the present invention. The pedestal 300′ is shown schematically.Likewise, FIG. 5 presents a cross-sectional view of a pedestal 300′ ofthe present invention, in an alternate embodiment. The pedestal 300″ isagain shown schematically. In each view, a reticle 222 is shown beingsupported on the respective pedestal 300′, 300″. Further, in each view acover 315 is provided. The cover 315 may be configured in accordancewith the cover 215 shown in the exploded view of FIG. 2. The cover 315is preferably fabricated from a dielectric material. The use ofdifferent dielectric material thickness is to adjust or control therelative RF power coupled to the reticle. One benefit of using adielectric material is it enables the use of two control knobs, that isknobs for dielectric constant and thickness. This, in turn, enables theoperator to change the relative amounts of RF that goes into the reticleversus the RF power that goes to the pedestal area surrounding thereticle. The dielectric thickness and type may be such that the relativeamount is the same for uniform power distribution, or different ifneeded for compensating for the etch process.

Dielectric material is shown at 318 in both FIG. 4 and in FIG. 5. InFIG. 4, the dielectric material 318 resides along the top of the uppersupport base 306. In FIG. 5, the dielectric material 318 definessubstantially the entire thickness of the upper support base 306. Ineither instance, the dielectric material 318 is preferably placedoutside of the contact point for the reticle 222 on the pedestal 300.

As can be seen, the pedestals 300, 300′, 300″ place dielectric materialalong a periphery of the upper substrate support body 306. Thedielectric material 318 may be polymeric or ceramic. An example of apolymeric material is Ardel™ polyarylate material manufactured by Amocopolymers. Another example is Vespel™ polyimide from DuPont. Stillanother example is a plastic material sold under the trade name Ultem™.Yet another example is a synthetic rubber material. An example of asuitable ceramic material is aluminum oxide. Another example of anacceptable dielectric material is quartz. The selected use of dielectricmaterial 318 has the effect of changing the amount of RF power couplinginto the reticle during a plasma etching procedure. In this respect,during a plasma etching procedure, the body 306 receives power, such asan RF power. By using dielectric material on the periphery of the body,the potential drop across the pedestal is changed to have a value lessthan the region where the reticle rests, i.e., inside of the substratesupport ridge 326. The portion of the pedestal 300 within the substratesupport ridge 326 remains metallic in order to efficiently conduct wasteheat away from the reticle 222.

While the foregoing is directed to embodiments of the present invention,other and further embodiments of the invention may be devised withoutdeparting from the basic scope thereof, and the scope thereof isdetermined by the claims that follow.

1. A pedestal for supporting a substrate in a plasma etching chamber,comprising: a body, the body being configured to receive an RF power;and a substrate support base along an upper surface of the body, thesubstrate support base having an outer edge, and an intermediatesubstrate support ridge for receiving and supporting the substrate; andwherein at least a portion of the substrate support base outside of theintermediate substrate support ridge is fabricated from a dielectricmaterial.
 2. The pedestal of claim 1, wherein the portion of thesubstrate support base within the substrate support ridge is fabricatedfrom a metallic material.
 3. The pedestal of claim 2, wherein theportion of the substrate support base fabricated from a dielectricmaterial is formed by placing a layer of dielectric material along a topsurface of the substrate support base outside of the substrate supportridge in order to form a dielectric ring.
 4. The pedestal of claim 3,wherein the substrate support ridge is fabricated from a metallicmaterial.
 5. The pedestal of claim 3, wherein the dielectric material isfabricated from materials selected from the group consisting of apolymeric material, a ceramic material, and combinations thereof.
 6. Thepedestal of claim 2, wherein the portion of the substrate support basefabricated from a dielectric material defines substantially the entirethickness of the substrate support base outside of the substrate supportridge.
 7. The pedestal of claim 6, wherein the substrate support ridgeis fabricated from a metallic material.
 8. The pedestal of claim 6,wherein the dielectric material is fabricated from materials selectedfrom the group consisting of a polymeric material, a ceramic material,and combinations thereof.
 9. The pedestal of claim 1, further comprisinga cover configured to be received on the substrate support base.
 10. Apedestal for supporting a reticle in a plasma etching chamber,comprising: a body, the body being configured to receive an RF power; areticle support base along an upper surface of the body, the reticlesupport base having an outer edge, and an intermediate reticle supportridge for receiving and supporting the reticle; and wherein at least aportion of the reticle support base outside of the intermediatesubstrate support ridge is fabricated from a dielectric material. 11.The pedestal of claim 10, wherein: the portion of the reticle supportbase within the reticle support ridge is fabricated from a metallicmaterial; the reticle support ridge is fabricated from a metallicmaterial; and
 12. The pedestal of claim 10, wherein the dielectricmaterial is fabricated from at least one of a polymeric material and aceramic material.
 13. The pedestal of claim 12, wherein the portion ofthe reticle support base fabricated from a dielectric material is formedby placing a layer of dielectric material along a top surface of thereticle support base outside of the reticle support ridge in order toform a dielectric ring.
 14. The pedestal of claim 12, wherein theportion of the reticle support base fabricated from a dielectricmaterial defines substantially the entire thickness of the reticlesupport base outside of the reticle support ridge
 15. A plasma etchingchamber having a pedestal therein for supporting a reticle, comprising:a chamber body defining a base wall, a side wall and a dome; a gatealong the side wall for permitting a reticle to be moved into the plasmaetching chamber; and a reticle support member for supporting a reticlewithin the plasma etching chamber during processing, the reticle supportmember comprising: a body, the body being configured to receive an RFpower; a reticle support base along an upper surface of the body, thereticle support base having an outer edge, and an intermediate reticlesupport ridge for receiving and supporting the reticle; and wherein atleast a portion of the reticle support base outside of the intermediatesubstrate support ridge is fabricated from a dielectric material. 16.The chamber of claim 15, wherein: the portion of the reticle supportbase within the reticle support ridge is fabricated from a metallicmaterial; the reticle support ridge is fabricated from a metallicmaterial; and
 17. The chamber of claim 16, wherein the dielectricmaterial is fabricated from at least one of a polymeric material and aceramic material.
 18. The chamber of claim 17, wherein the portion ofthe reticle support base fabricated from a dielectric material is formedby placing a layer of dielectric material along a top surface of thereticle support base outside of the reticle support ridge in order toform a dielectric ring.
 19. The chamber of claim 17, wherein the portionof the reticle support base fabricated from a dielectric materialdefines substantially the entire thickness of the reticle support baseoutside of the reticle support ridge